perl实现二分法的ip查找

sub search_newarea{
     my $ip =@_[0];
     $start=1;
     $end=$count;
     @ips=split(/\./,$ip);
     $long_ip =int($ips[0])*256*256*256+int($ips[1])*256*256 + int($ips[2])*256 + int($ips[3]);
     while($start <= $end && $start >= 1 && $end <= $count){
            $middle=int(($start+$end)/2);
            if($long_ip>=$areas{$middle}[0] && $long_ip<=$areas{$middle}[1]){
                 return $areas{$middle}[2];
            }
            if($long_ip>$areas{$middle}[0]){
                  $start=$middle+1;
            }else{
                 $end=$middle-1;
            }

     }
     return 0;
}

 

search_newarea $ip;